This invention relates to a solid state digital thermometer having a number of additional useful features for use in a spa, hot tub, bathtub or swimming pool. Spas are typically utilized out-of-doors away from readily available clocks or time pieces. Because spas are typically operated and used at an elevated temperature, it is advantageous to have readily available a thermometer which enables users to determine the water temperature of the spa.
The usefulness of a floating spa thermometer is disclosed in, for instance, U.S. Pat. No. 4,503,563 in which a combination light, temperature probe and radio is adapted to float within a spa. A handle enables it to be used as a portable lantern or radio. A somewhat more primitive device is disclosed in U.S. Pat. No. 4,435,095, wherein a glass mercury thermometer is provided to measure the temperature of a hot tub.
Digital display thermometers are well-known. For example, U.S. Pat. No. 4,444,517 discloses an electronic clinical thermometer having a magnetic reed switch requiring that, once activated, the thermometer must be placed in a magnetic field to break the contact to the battery. The device is watertight and is not provided with illumination means for use at night. Also, U.S. Pat. No. 4,601,589 is an electric thermometer powered by a solar cell having a digital display of temperature.
Lastly, a pair of swimming pool alarms are disclosed in U.S. Pat. Nos. 3,969,712 and 3,054,096. Both devices utilize motion-sensitive switches responsive to waves in the pool, setting off alarms to indicate that, for instance, a child has fallen into the pool.